Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Ceramic Society
Journal Basic Information
Journal DOI :
The Korean Ceramic Society
Editor in Chief :
Volume & Issues
Volume 37, Issue 12 - Nov 2000
Volume 37, Issue 11 - Nov 2000
Volume 37, Issue 10 - Oct 2000
Volume 37, Issue 9 - Sep 2000
Volume 37, Issue 8 - Aug 2000
Volume 37, Issue 7 - Jul 2000
Volume 37, Issue 6 - Jun 2000
Volume 37, Issue 5 - May 2000
Volume 37, Issue 4 - Apr 2000
Volume 37, Issue 3 - Mar 2000
Volume 37, Issue 2 - Feb 2000
Volume 37, Issue 1 - Jan 2000
Selecting the target year
Reclamation of Waste Lubricating Oil Using Ceramic Micro/Ultrafiltration Composite Membrances
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 403~409
The permeation characteristics and reclamation efficiency of waste lubricating oil were studied as a function of the types of ceramic composite membranes and the membrane separation process variables. The oil permeability of the TiO2 composite membrane(pore size 0.015
) was directly proportional to the crossflow velocity(0.22∼0.9 m/s) and temperature(150
). In the batch concentration process, as the concentration factor increased, both the permeability and the ash content of the permeate decreased. The average ash contents of the total permeate through the A6 alumina membrane(average pore size 0.8
), Z1/A6 and Z1/A4(pore size 0.23
)/A7(pore size 6
) zirconia composite membrances(average pore size 0.07
) were about 0.063 wt%, 0.045wt% and 0.08wt% in the region of 1∼2 concentration factor, respectively. The ash content of the mixed permeate through the A6 alumina and zirconia composite membrane was about 0.06 wt% and it can be also reduced to 0.06 wt% in the Z1/A6 membrane and below 0.003 wt% in the TiO2/Z1/A6 membrane. It was concluded that the treated oil obtained from the multi-step membrane separation process could be used as reclaimed lubricating oil as well as reclained fuel oil.
Effects of Portland Cement Characters and Working Temperature on the Physical Properties of Cement Mortars
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 410~417
In this study the effects of specifics surface area of cement, addition amount of gypsum and substitution ratio of gypsum anhydrite ont he physical properties of cement mortars were investigated by measruements of setting time, flow, compressive strength and hydration heat evolution rate. The results showed that fluidity of mortars was increased by 40 wt.% of maximum flow change with the decreasing specific surface area of cement from 3,500
/g to 3,300
/g and affected by the relationship between the cement and balancing between the chemical activityof cement and solubility of calcium sulfate are desirable to prevent the fluidity of concrete from decreasing by high temperature in summer season.
Effect of Ion Damage on the Crystallization of PZT thin films
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 418~424
Effects of Ar ion damage prior to the phase transformation from pyrochlore to perovskite structure of PZT thin films have been investigated. As the degree of damage increased by increasing the acceleration voltage in the ion mass doping system, the phase transformation temperature decreased such that the temperature could be lowered down to 550
when the film was damaged at 15 kV for 5 minutes. When the film was damaged prior to the heat treatment grain size of the perovskite thin films became less than 300
. It turned out that relatively high value of the remanent polarization (about 30
) as well as improvement of the fatigue characteristics to a large extent is closely related to the fine grain size of thus obtained PZT films.
Nanoparticulate Co-Ferrite Thin Films on Glass Substrate Prepared by Sol-Gel Method
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 425~431
Cobalt ferrite thin films on Corming glass substrate were fabricated by a sol-gel method. Cobalt ferrite thin films with the grain size of 20-35 nm and thickness of 50nm were obtained. Rapid thermal annealing (RTA) and Annealing processes were adopted for comparison of characteristics of the films. Coercivity values were changed with thermal condition and magnetization values were increased as a function of soaking time. With prolonged soaking time, however, it was decreased because of the diffusion of cations from the glass substrate. The RTA process in preparation of cobalt ferrite thin film was the effective way to prevent and to form a single spinel phase in reduced soaking time. The film heated at 600
for 30 minutes by RTA had coercivity of 2,600 Oe, saturation magnetization 460 emu/㎤, and Mr
of 1.43 memu/
The Thermoelectric Properties of p-type SiGe Alloys Prepared by RF Induction Furnace
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 432~437
Thermoelectric properties of p-type SiGe alloys prepared by a RF inductive furnace were investigated. Non-doped Si80Ge20 alloys were fabricated by control of the quantity of volatile Ge. The carrier of p-type SiGe alloy was controlled by B-doping. B doped p-type SiGe alloys were synthesized by melting the mixture of Ge and Si containing B. The effects of sintering/annealing conditions and compaction pressure on thermoelectric properties (electrical conductivity and Seebeck coefficient) were investigated. For nondoped SiGe alloys, electrical conductivity increased with increasing temperatures and Seebeck coefficient was measured negative showing a typical n-type semiconductivity. On the other hand, B-doped SiGe alloys exhibited positive Seebeck coefficient and their electrical conductivity decreased with increasing temperatures. Thermoelectric properties were more sensitive to compaction pressure than annealing time. The highest power factor obtained in this work was 8.89
s for 1 at% B-doped SiGe alloy.
Effects of Various Kinds of Calcium sulfates on the Early Hydration of Belite-rich Cement
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 438~443
This dissertation is focused on the study over the improvement for the early strength of belite-rich cement(BRC). For this purpose, the initial hydration behaviors according to addition of different calcium sulfate types were evaluated. From the observations by XRD, DSC and SEM, the BRC II and III with the addition of natural anhydrate and flue gas desulphurization(FGD) gypsum, respectively, formed much ettringite after 7 days more than the BRC I with the addition of chemical gypsum. The compressive strength of the BRC II and III developed outstandingly due to the formation of calcium aluminate hydrate within pores of hardened BRC paste. Especially, in the case of BRC III adding FGD with low impurities, the early as well as long term compressive strengths were shown very high, compared with other specimens.
Fabrication of Fiber-Reinforced Composites by High Pressure Self-Combustion Sintering Method
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 444~452
Dense composites of titanium matrix and Al2O3 matrix with reinforcements of carbon or titanium carbide fibers were successfully fabricated by high-pressure self-combustion sintering method or combustion reacton under 30 MPa of uniaxial pressure with an aid of external heating in vaccum. It was found that the fibers were uniformly distributed in the matrix, and aligned in a phase perpendicular to the pressure axis. As a moel ratio of Ti/C or reaction time increased, the density of Ti-matrix composite increased Micro pores around fibers could be removed by using clean carbon fibers without sizing agent on their surface. The evolution of carbide fibers from carbon fibers was observed. The composition of the various phases around fibers were analyzed.
Effect of Chemical Composition on the Latent Hydraulic Activity of Blast Furnace Slag
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 453~458
Glasses showing the composition of blast furnace slag were made in the laboratory, and the effect of the chemical composition on the latent hydraulic activity of the slags was examined. The latent hydraulicity was greatly influenced by the composition change, the optimal characteristic of the hydraulicity was achieved at the slag composition of 47CaO:20Al2O3:33SiO2. The content of CaO and Al2O3 were not equivalent to the hydraulic activity of the slags as the b-formula (KS L 5210) indicates. Good latent hydraulicity was shown when Al2O3 was richly contained at the high (CaO＋Al2O3):SiO ratio, while the more the MgO content was, the more negative the result turned out.
Synthesis and Hydration Property of 3CaO.
Clinker by Solid State Reaction
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 459~465
3CaO.3Al2O3.CaSO4(C4A3)clinker was prepared by solid state reaction and then its hydration property was investigated. C4A3 clinker was fired at various temperatures in the range of 700~135
. The hydration of it was studied by XRD, DSC, Solid-state 27Al MAS NMR and SEM. According to the results, the Ca4A3 clinker was produced by reacting calcium aluminates with CaSO4 and Al2O3 and C4A3 was formed as a main phase after calcining at 120
. The hydration products were mainly calcium monosulfoaluminate hydrate and Al(OH)3, and they were produced after 2hrs of hydration. However the hydration rate was about 74% at 3days.
Electrical Characteristics of Cathode Li(
Substituted by Transition Metals in Li-Ion Secondary Batteries
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 466~472
As cathode materials of LiMn2O4-based lithium-ion secondary batteries, Li(Mn1-
)2O4 (M=Ni and Co,
=0, 0.05, 0.1 and 0.2) materials which Co and Ni are substituted for Mn, were syntehsized by the solid state reaction at 80
for 48 hours. No second phases were formed in Li(Mn1-
)2O4 system with substitution of Co. However, substitution of Ni caued to form a second phase of NiO when its composition exceeded over 0.2 of
)2O4. As the results of charging-discharging test, the maximum capacity of Li(Mn1-
)2O4 appeared in
=0.1 for both Co and Ni. Also, Li(Mn1-
)2O4 electrode showed higher capacity and better cycle performance than LiMn2O4.
Formation Mechanism of Ultrafine
Powders from Aqueous
Solution by Homogeneous Precipitation Process at Low Temperature
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 473~478
The TiO2 powder with the values of the large specific surface area more than 150
/g has been prepared with the homogeneous precipitation process below 5
and its formation mechanism was investigated using the SEM, TEM and Raman Spectroscopy. With the spontaneous hydrolysis of aqueous TiOCl2 solutions, all the precipitates were fully and homogeneously crystallized with the rutile TiO2 phase simply by heating, which as transformed to the anatase TiO2 phase as increasing the addition of SO42- ions to the aqueous TiOCl2 solution. The precipitates were formed with spherical secondary particles which consisted of acicular, spherical and mixed primary particles corresponding to the rutile, anatase and mixed phases, respectively. It can be thought that the formation and phase determination of crystalline TiO2 powders even at ambient temperature would be related with the existence of the capillary force. This force might be varied depending on the shape change of the primary particles.
Correlatin between the Microstructure and the Electrical Conductivity of SOFC anode, Ni-YSZ : I. Microstructure Analysis
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 479~490
The microstructure of Ni-YSZ composite as an anode of SOFC was investigated as a function of Ni content(10-70 vol%) in order to examine the correlation between microstructural-and electrical property. Image analysis based on quantitative microscopy theory was performed to quantify the microstructural property. We could get the informations about the size and distribution, contiguity and interfacial area of each phase or between the phases from the image analysis. According to the image analysis, contiguity between the same phae was mainly dependent on the amount of the phase while the contiguity between different phases was additionally influenced by the microstructural changes, especailly by the coarsening of the Ni phase. The whole length of pores perimeter was increased as Ni content increased, which indicated the overall microstructural evolution was mostly related with the coarsening of Ni phase. Ni-Ni interfacial area was also gradually increased as Ni content increased but controlled by pore phase at low Ni content region and by YSZ phase at intermediate Ni content region. These quantified microstructural properties were used to characterize the electrical properties of Ni-YSZ composite.
Ordering Structures of B-Site Cations in Pb(
-Based Solid Solutions
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 491~496
Single phae Pb(Mg1/3Nb2/3)O3-based solid solutions, the Mg2+ of which are replaced by 20mol% of Ni2+, Zn2+, Cd2+, and the Pb2+ of which are replaced by 0∼20 mol% of La3+, were synthesized and their ordering structures of B-site cations were investigated by XRD and TEM. The B'-site cations (Mg2+, Ni2+, Zn2+, Cd2+) are disordered while these B'-site cations and the B"-site cations (Nb5+) are nonstoichiometrically 1:1 ordered within the ordered nano-domains dispersed in the Nb5+-rich disordered matrix. The charge imbalance between the B'-rich ordered nano-domains and the B"-rich disordered matrix are compensated by the doping of electron donor such as La3+, which enhances the degree of nonstoichiometric 1:1 ordering. For a given La3+ content, the degree of nonstoichiometric 1:1 ordering increases as the average ionic size difference between the B'-and B"-site cations increases, Ni2+
Synthesis of Mullite-Zirconia Composites from Kaolin by Gel Coating
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 497~504
In this study, mullite-zirconia comosite was fabricated by adding ZrOCl2.8H2O using of boehmite gel coating to Hadong kaolin (pink A grade) in order to enhance strength of the mullite specimens. The influence of ZrOCl2.8H2O content and fireing temperature on the crystall phase, microstructure, bulk density, strength of the specimens was investigated. Mullite-zirconia composite was produced in the process of coating zirconia to mullite powder synthesized thereafter and mixing simultaneously of starting materials with boehmite-zirconia gel. Maximum strength with in this study was 251 sintered at 1
for 2h. Bulk density and strength of the composite with zirconia coated mullite was higher than simultaneous on mixture of starting materials.
The Study of Reaction Bonded Silicon Nitride Fabricated Under Static Nitrogen Pressure
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 505~510
In this investigation, we fabricated RBSN (Reaction Bonded Silicon Nitride) using the static nitriding system which could be advantageous for commercialization. Firstly, Si compacts of different sizes were made, and then nitridation rates were investigated as a function of added static gas pressure. The reaction schedule was obtained by pre-experiments. In case of small samples, the variation of
phases between the inside and the outside region of the specimens was examined after the samples were nitrided under 1 bar and 1.5 bar reaction pressure. On the other hand, large samples of Si compact with the size of 36 mm for diameter and 23 mm for thickness were nitrided for 26 hours of the total nitridation time, which showed a complete and homogeneous nitriding reaction from the outside to the inside of the samples, although the time was considerably shorter than that needed for convertional nitridation. Nitridation rates obtained at the early stage of reaction were proportional to the reaction gas pressures. The sequences of the nitridation reaction with the thickness were as follows 1) the outside, 2) the inside and 3) the intermediate area of the specimen. These results wer eobtained from the coloration of cross sectioned specimens that had various nitridation rates. Total nitriding reaction kinetics was controlled by chemical reaction, not by diffusion of the nitrogen gas.
The Effect of
ion Dissolution on Microstructural Changes and Electrical Properties in
Aqueous Slurry System
Journal of the Korean Ceramic Society, volume 37, issue 5, 2000, Pages 511~515
The effect of Ba2+ ion dissolution with different pH and amount of PAA on microstructural changes of green and sintered bodies and its electrical properties was studied in aqueous nano-size BaTiO3 slurry system. The dissolution of Ba2+ was least at strong base, pH 10.8 and by addition of amount of 0.15 wt% PAA. The green body with the lowest of dissolution of Ba2+ at pH 10.8 and 0.15 wt% PAA had minimum values of average pore size, 40nm and shown high increase of sintered density. The compact sintered at 125
for 2 hr with highest Ba2+ dissolution had low density and dielectric constant due to abnormal grian growth. However, the sintered body with the lowest Ba2+ dissolution had high sintered density and then shown high dielectric constant.